Device for actuating the knife of a sewing machine



Jan. 26, 1965 L. BONO 3,167,042

DEVICE FOR ACTUATING THE KNIFE OF A SEWING MACHINE Filed July 27, 1961 2 Sheets-sheaf. 1

i I Z2 a INVENTOR Luzga 502w ATTORNEYS Jan. 26, 1965 BONO 3,167,042

DEVICE FOR ACTUATING THE KNIFE OF A SEWING MACHINE Filed July 27. 1961 2 Sheets-Sheet 2 4 x C Q INVENTOR Lugw' 5027/0 ATTORNEYS United States Patent ice 6 Claims. hi. 112-123 This invention relates in general to new and useful improvements in attachments for sewing machines, and more particularly to a knife attachment for a sewing machine.

A primary object of this invention is to provide a novel knife attachment for a sewing machine, the knife attachment being of the type wherein it may be readily secured to the arm of a sewing machine and driven from the usual rotating shaft within the arm for reciprocating the needle bar.

Another object of this invention is to provide a novel knife attachment for a sewing machine having drive means for driving the same to effect a reciprocation thereof, the knife attachment including a pivot pin having a lever projecting therefrom with the lever being connected to a knife support for effecting the reciprocation of the knife support as the lever is oscillated, the pivot pin carrying a second lever which is continuously oscillated through the connection thereof to a continuously rotating shaft customarily found in a sewing machine, and there being provided means for selectively coupling the oscillating lever to the pivot pin for effecting the oscillatory movement of the pivot pin and the resultant oscillatory movement of the lever which is connected to the knife support.

Still another object of this invention is to provide in a knife attachment, a novel support and drive assembly, the support and drive assembly being of a nature wherein the same basic support and drive assembly may be utilized in conjunction with either a vertically reciprocating knife or a horizontally swinging knife.

A further object of this invention is to provide a novel coupling assembly for effecting the driving of a knife attachment of a sewing machine, the coupling assembly ineluding a hollow pivot pin mounted for rotation, a lever rotatably journaled on the pivot pin for continuous oscillatory movement, a second lever rigidly secured to the pivot pin and being disposed alongside the first lever, ae

rod extending through the pivot pin and carrying a tooth which slidably passes through the second lever and is selectively engaged in a notch in the face of the first lever for effecting the coupling of the first lever to the pivot pin to drive the pivot pin from the first lever, and there being a spring extending between the two levers for urging the levers out of angular alignment wherein the tooth may be shifted to a position where it is out of alignment with the notch in the first lever in all positions of the first lever to provide for a permanent disconnect.

With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims and the several views illustrated in the accompanying drawing.

In the drawing:

FIGURE 1 is a perspective view of an embodiment of the invention applied to a sewing machine with the device shown in a drive disengaged position, the sewing machine being schematically illustrated for purposes of clarity.

FIGURE 2 is a top view of the knife attachment shown in FIGURE 1, but with the drive coupling thereof in the engaged position, a portion of the pivot pin and the sup port therefor being broken away and shown in section.

FIGURE 3 is a transverse vertical sectional view taken along the line III-III of FIGURE 2, and shows further 3,167,5542 Patented Jan. I 26, 1 965 the details of the knife attachment, all portions of the sewing machine being omitted.

FIGURE 4 is an elevational view of a modified form of knife attachment with the support and pivot pin thereof broken away and shown in section, the attachment being illustrated as secured to a portion of a sewing machine with the sewing machine also being broken away and shown in section.

Referring now to the drawings in detail, it will be seen that in the embodiment of FIGURES 1, 2 and 3, there is illustrated a portion of a conventional type of sewing machine which includes an arm 1. A horizontally disposed shaft 2 is mounted in the arm 1 in the customary manner and is continuously rotated during the operation of the sewing machine. The sewing machine also includes the customary needle bar 3 which is vertically slidable in a bushing 4 carried by the arm 1. The needle bar 3 is connected to the rotating shaft 2 in a customary manner (not shown). A second substantially vertical bushing 5 is also mounted in the arm 1 in the customary manner and carries a presser bar 6 for vertical reciprocatory movement. The presser bar 6 has a screw 7 in the lower end thereof which releasably secures the customary presser foot 8 to the lower end of the presser bar 6.

In accordance with this invention, there is secured to the underside of the arm 1 a knife attachment which includes a support 22 having holes 23 (FIGURE 2) through which screws (not shown) may be passed to secure the support 22 to the underside of the arm 1 immediately adjacent the needle bar 3 and the presser bar ti. A horizontally disposed pivot pin 21 extends through and is rotatably journaled in the support 22. A lever 10 is mounted on the pivot pin 21 for oscillatory movement relative thereto. The lever 10 is driven from the rotating shaft 2 by means of an eccentric 9 secured thereto. The eccentric 9 is received in one end of a connecting rod 13 and the opposite end of the connecting rod 13 carries a pin 14. A shaft 16 is suitably journaled within the arm 1 in parallel relation to the shaft 2 in a manner not shown. One end of the shaft 16 carries an arm having a slot 19 in which the pin 14 is positioned for relative sliding movement. The arm 15 is retained on the pin 14 by means of a nut 20. V j

The opposite end of the shaft 16 is provided with an arm 17 which, in turn, has pivotally connected thereto the upper end of a link 18. The lower end of the link 18 is pivotally connected to the lever 10. Thus, it will be apparent that as the shaft 2 rotates, the lever 10 will be oscillated.

The pivot pin 21 is a part of a lever 24 which lever 24- includes an arm 25 which is rigidly secured to the pivot pin 21 for swinging movement therewith. The arm 2-5 is disposed adjacent the lever 10 and has a radially extending slot 26 in the outer portion thereof.

The pivot pin 21is hollow and contains within it an elongated rod having a push button 27 for effecting the reciprocation of the rod through the pivot pin 21. The rod, which is referred to by the numeral 28, has on the end thereof remote from the push button 27 a small plate 29 which, in turn, carries a tooth 30. The tooth 30 is reversely disposed as compared with the rod 28 and is generally parallel thereto. The tooth 30 extends through the slot 26in the arm 25 and opposes a side surface 11 of the lever 10. The side surface 11 is interrupted by a notch or slot 12 in which the end of the tooth 30 is adapted to be engaged to couple the lever 10 to the pivot pin 21 through the arm 25 and the tooth -.30.

It is to be noted that the rod 28 is urged to the right, as viewed inFIGURE 2, by a spring 31 disposed within the pivot pin 21. The spring 31 retains the tooth 30 either within the notch 12 in the surface 11 or in bearing engagement with the surface 11. It is to be machine.

noted that the spring 31 acts between a shoulder 32 formed internally of the pivot pin 21 and an exterior shoulder 33 on the rod 28 adjacent the push button 27.

A coil spring 34 is positioned on that portion of the pivot pin 21 disposed between the lever and the arm 25. 'One end of the spring 34 is connected to the lever 10 while the other end thereof acts on the arm 25. The purpose of the spring 34 is to swing the arm out of angular alignment with the lever 11 when the tooth is released from the notch 12. The movement of the arm 25 is such that the tooth 30, while it will continue to ride on the surface 11 of the lever 16), will remain out of alignment with the notch 12 in all positions of the lever 1%) during the movement thereof.

An arm 35 is secured to the right end of the pivot pin 21, as viewed in FIGURE 2. The arm 35 is clamped on the pivot pin 21 by means of a screw 36 extending through a split portion thereof, as is best shown in FIG- URE 3. The arm 35' has an extension in the form of a handle 37 which may be depressed in the direction of the arrow y in FIGURES 1 and 2 to rotate the arm 25 to move the'tooth 30 into a position where it is aligned with the slot 12 of the lever it). In this manner, the tooth 30 can again be engaged in the slot 12 by the urgence of the spring 31 acting upon the rod 28. It will be readily apparent that when the tooth 3ft is engaged in the notch 12 of the lever 10, the lever 24 will oscillate with the lever 10 and result in the oscillation of the arm 35.

In accordance with the invention, there is provided a vertically acting knife, generally referred to by the numeral 38. The knife 38 has a blade 39 which is fastened to a slide block by means of screws 41 which engage in a vertical slot 42 in the blade 39 to permit vertical adjustment of the blade 39. The slide 40, in turn, is

slidable within a horizontal guide 43 of a support 44 and is secured in an adjusted position by means of a screw 45 which passes through a slot 46 in the slide 40.

The support 44 is provided with a vertical bore 47 which, in turn, receives a depending substantially vertical guide pin 48 secured to the underside of the support 22. In this manner, the support 44 is mounted for vertical reciprocatory movement only.

The support 44 also has attached thereto a forked arm 49 which engages the bushing 5 of the presser bar 6 and serves to orient the support 44 and the knife 38 carried thereby. The fork 49 is of the split type, as is shown in FIGURE 2, and carries an adjusting screw 50 which makes it possible to adjust the opening of the fork 49 in such a manner that the play between the fork 49 and the bushing 5 may be adjusted.

The support 44 also carries a horizontal pin 51 which is connected to a horizontal pin 52 carried by the arm 35 by means of a small connecting rod or link 53. By means of this connecting rod, the oscillations which the swinginglever 10 transmits to the arm 35 are transformed into vertical reciprocatory movement of the knife 38 in the direction determined by the guide pin 48 and the bushing 5. e

In FIGURES 2 and 3, there are shown grooves 54, 55, 56, 57 and 58 in the support 22. An oil soaked wick is disposed in these grooves for the purpose of providing lubrication for the pivot pin 21 and the guide pin 48.

Reference is now made to FIGURE 4, wherein there is shown a modified form of the invention. In FIGURE 4, there is illustrated a portion of the conventional arm 1 of a sewing machine in which there is mounted for rotation a shaft 2 which drives the needle bar of the sewing A short shaft 2:: is rotatably journaled within the arm 1 in parallel relation to the shaft 2. The shaft 2a is driven from the shaft 2 by means of a belt 71 which is engaged over a pulley 72 carried by the shaft 2a and a pulley 73 carried by the shaft '2.

A knife attachment of the same general type as the 'knife attachment of FIGURES 1, 2 and 3 is secured to 1 the arm 1 on the sewing machine. The knife attachment includes a support 22a which is constructed like the support 22 and is secured to the underside of the arm 1. The support 22a carries a lever, generally referred to by the numeral 24a, which lever includes a pivot pin 21a which extends through the support 22a and is rotatably journaled therein.

A lever 19a is rotatably journaled on the pivot pin 21a to the left of the support 22a and is provided with a fork '74 at the extreme end thereof engaged with an eccentric 9a carried by thershaft 2a. Thus, as the shaft 2a is driven from the shaft 2, the eccentric h, acting on the fork 74, will oscillate the lever 10a.

The lever 24a includes an elongated arm 25a which is rigidly secured to the pivot pin 21a and projects to opposite sides thereof. The lever liia has a side surface 11a opposing the arm 25a, and the surface lla has a notch 1.2a formed therein. That portion of the arm 25a disposed adjacent the surface lla of the lever llfia is provided with a notch within the extreme end thereof.

A rod 24% extends through the pivot pin 21a, which pivot pin Zia is hollow, and has a push button 27a secured to the right end thereof. A small plate 2% is secured to the left end of the rod 28a with the plate 29:; terminating in a reversely directed tooth 30a which extends through the notch in the end of the arm 25a and is engageable in the notch 12a to couple the lever 24a to the lever Ma.

The rod 28a is urged to the right by means of a spring which reacts against both the pivot pin 21a and the rod 28a in the same manner as described with respect to the spring 31. Also, a spring 34a is carried by the pivot 21:; between the lever Etta and the arm 25a and is connected to the two so as to rotate the arm 25a with respect to the lever lltia when the tooth 36a is disengaged from within the slot 12a of the lever 16a to Inisalign the tooth 38a with the notch 12a in all positions of the lever film, as described with respect to the spring 34. An arm 35a is clamped to the right end of the pivot pin and carries a handle 37a for the purpose of rotating the lever 24a to again align the tooth 30a with the notch 12a.

The knife attachment of FIGURE 4 also includes a knife 38a which includes a blade 39a. The blade 39a is fastened by means of a screw 59 to a rod 66 of square section which is slidable within guides 61 of a support 62. The rod 59 terminates at its upper end in a threaded stem 63 on which there are screwed a nut (64 and a lock nut 65 to maintain a vertically adjusted position of the rod 60, and thus a vertically adjusted position of the knife 38a.

' The support 62 is carried by a substantially horizontal guide 67 and is secured thereto in an adjusted position by means of a screw 66. The horizontal guide 67 is disposed generally perpendicular to the axis of the pivot pin 21a. The guide 67, in turn, is located on a part 68 which is slidable parallel to the axis of the pivot pin 21a along a horizontal bracket 69 of the arm 25a.

It is to be noted that the arm 25a oscillates in a vertical plane. The support for the knife 38a is secured to that portion of the arm 25a which projects downwardly, and thus movement of the blade 38a is generally horizontal through a slight arc in a vertical plane.

From the foregoing, it will be readily apparent that there has been devised highly desirable structure for carrying out the intended purpose. Although two embodiments of the invention have been illustrated, it is to be understood that the invention is not limited to the exact details of the embodiments, but minor changes may be made in the structure disclosed within the spirit and scope of the invention, as defined by the appended claims.

What is claimed as new:

1. A knife attachment fora sewing machine comprising a support adapted to be connected to an arm of a sewing machine, a hollow pivot pin carried by said support for osciilatory movement, arm means secured to said pivot pin for oscillation therewith, means connected to said support for mounting a knife for reoiprocatory movement from said pivot pin, a lever having a notch disposed therein pivotally mounted on said pivot pin, drive means operatively connected to said lever for oscillating said lever, a rod disposed within said hollow pivot pin and movable axially with respect thereto, tooth means carried on said rod and being disposed toward said notch, a second arm means secured to said pivot pin and having an opening therethrough in which said tooth slidably passes, spring means disposed between said pivot pin and said lever for pivoting said tooth out of alignment with said notch, biasing means engaging said rod to normally urge said tooth towards said lever, and means connected to said rod to move same axially against the action of said biasing means when said tooth is engaged in said notch so that said spring means pivots said tooth out of alignment with said notch to disengage said tooth therefrom and maintain said tooth out of engagement therewith, said first mentioned arm means being operated radially with respect to said last mentioned means against the action of said spring means so that said biasing means moves said rod axially to cause said tooth to engage said notch.

2. The knife attachment of claim 1, wherein said means for mounting a knife includes a knife support, means guiding said knife support for linear movement, and

linkage means connecting said first mentioned arm means to said knife support.

3. The knife attachment of claim 1 wherein said means for mounting a knife includes a knife support having veritcal movement only.

4-. The knife attachment of claim 1 wherein said means for mounting a knife includes a knife support, a guide depending from said first mentioned support, and means mounting said knife support on said guide for vertical movement only.

5. The knife attachment of claim 1 wherein said means for mounting a knife includes a knife support, a guide depending from said first mentioned support, means mounting said knife support on said guide for vertical movement only, and a fork carried by said knife support for guided engagement with the usual sewing machine presser bar bushing.

6. The knife attachment of claim 5 wherein said fork has regulating means for taking up play between a presser bar bushing and said knife support.

References Cited in the file of this patent UNITED STATES PATENTS 511,603 Fefel Dec. 26, 1893 668,184 Hill et al Feb. 19, 1901 2,538,271 Reimer et al Jan. 16, 1951 2,977,910 Covert Apr. 4, 1961 

1. A KNIFE ATTACHMENT FOR A SEWING MACHINE COMPRISING A SUPPORT ADAPTED TO BE CONNECTED TO AN ARM OF A SEWING MACHINE, A HOLLOW PIVOT PIN CARRIED BY SAID SUPPORT FOR OSCILLATORY MOVEMENT, ARM MEANS SECURED TO SAID PIVOT PIN FOR OSCILLATION THEREWITH, MEANS CONNECTED TO SAID SUPPORT FOR MOUNTING A KNIFE FOR RECIPROCATORY MOVEMENT FROM SAID PIVOT PIN, A LEVER HAVING A NOTCH DISPOSED THEREIN PIVOTALLY MOUNTED ON SAID PIVOT PIN, DRIVE MEANS OPERATIVELY CONNECTED TO SAID LEVER FOR OSCILLATING SAID LEVER, A ROD DISPOSED WITHIN SAID HOLLOW PIVOT PIN AND MOVABLE AXIALLY WITH RESPECT THERETO, TOOTH MEANS CARRIED ON SAID ROD AND BEING DISPOSED TOWARD SAID NOTCH, A SECOND ARM MEANS SECURED TO SAID PIVOT PIN AND HAVING AN OPENING THERETHROUGH IN WHICH SAID TOOTH SLIDABLY PASSES, SPRING MEANS DISPOSED BETWEEN SAAID PIVOT PIN AND 